Conventionally, as a device for taking up a line body as mentioned above, a take-up device including means for pressing the line body while constantly holding the line body with a pair of flange rollers and a line press block and outputting a traverse inversion signal using a function of detecting that a layer of the line body is put on another layer of the line body has been proposed (Patent Document 1). A take-up control device for feeding the line body pitch by pitch and taking up the line body around a take-up bobbin with aligned winding has also been proposed (Patent Document 2).
Recently, electric devices, industrial motors and automobile driving motors have progressively become more energy-saving, more compact and higher in performance. In accordance with this, flat electric lines which can be taken up at a high density have been used more widely. For taking up a flat electric line fed from a flat electric line production apparatus, it is required to wind the flat electric line around a bobbin in a completely aligned manner. It is more preferable that the amount of the flat electric line wound around the bobbin is larger.
When the ratio of the width and the thickness (width/thickness) of a line body formed of the flat electric line having a rectangular cross-section is not large (especially when width/thickness<2), in order to increase the amount of the electric line wound around the bobbin (200 kg or more where the conductor is copper), the external shape of the bobbin needs to be enlarged. However, as the external shape of the bobbin is enlarged, the number of winds of the line body taken up around the bobbin in one layer, and also the number of wound layers around the bobbin, are increased.
More specifically, it is assumed here that a flat enamel line having a rectangular cross-section with a thickness T of 1 mm, a width W of 1.56 mm, and a corner chamfering R of 0.3 mm and using copper as a conductor is taken up around a bobbin formed of a cable drum according to the Japanese Design Patent Registration No. 1105143. When 250 kg of the line body is taken up around the bobbin, the number of winds in each layer is about 179 and the number of wound layers is 72.
However, it is difficult to realize completely aligned winding by the conventional art with the take-up device and the take-up control device described above because of the level of precision in terms of the position or shape of the flange of the bobbin and the level of precision in terms of the width of the line body.
In detail, a take-up bobbin is generally formed of wood, iron or a resin, but it is difficult to mold a bobbin without any variance in the position or shape of the flange or the variance in the thickness. In addition, the bobbin is used repeatedly and the flange of the bobbin is distorted as being used repeatedly.
For example, when the position of the flange of the bobbin is shifted by 0.8 mm, the line body partially has a clearance C of 0.8 mm at an inner edge of the flange or the bobbin is short of the area for winding the line body.
When the thickness of the flange of the bobbin is changed by 0.8 mm, the following occurs. When the bobbin is set to a take-up device, the position of the flange of the bobbin is shifted by 0.8 mm. Therefore, the traverse position does not conform to the bobbin. As a result, the line body wound around the bobbin has a clearance C of 0.8 mm throughout the circumference of the bobbin or the bobbin is short of the area for winding the line body.
In general, it is rare that the effective take-up width of a winding body of the bobbin around which the line body is to be taken up is an integral multiple of the width of the line body. This means that when the line body is taken up with aligned winding with no gap, a clearance C smaller than the width of the line body is made between the flange and the line body. When such a take-up method is used, a clearance C between the flange and the line body (hereinafter, referred to simply as the “clearance C”) is made or the bobbin is short of the area for winding the line body in most of the cases because of the variance in the position or shape of the flange or the change of the width of the line body.
When there is a clearance C at the inner edge of the flange and the clearance C is larger than a predetermined value, a part of the line body, which should be in the next layer, falls into the clearance C. As a result, the completely aligned winding cannot be realized (see FIG. 6). When the bobbin is short of the area for winding the line body, a part of the line body which should be in the underlying layer is put on the underlying layer as if this part was included in the next layer. In this case also, the completely aligned winding cannot be realized.
Even when a gap Δ is provided between adjacent winds of the line body in order to prevent a clearance C from being made at the inner edge of the flange, the size of the gap Δ between the adjacent winds of the line body needs to be chosen appropriately. Otherwise, there occurs a problem that a part of the line body in the next layer falls into the gap between the adjacent winds of the line body and so the completely aligned winding cannot be realized (see FIG. 7 (b)).
The width of the line body changes due to the production variance of the conductor and the insulating cover. For example, when the line body is to be taken up with 179 winds in one layer, a change of the width of 0.01 mm amounts to a change of 1.79 mm in total, which is larger than the width of the line body. When such a change occurs, the completely aligned winding cannot be realized with the conventional art.